The present invention relates to a power supply unit. More to particularly, this invention relates to a power supply unit which is improved such that it causes failure charging to be prevented on the occasion of use of non-charged-type battery in electric circuit device. In such the electric circuit device with charging function, the electric circuit device is capable of being received load-dispatching from any of an external power supply, a charged-type battery and/or a non-charged-type battery (dry cell).
In general, the electric circuit device such as a portable type radio cassette device, a scanner, and so forth are capable of being received load-dispatching from any one of the external power supply, the charged-type battery, and the non-charged-type battery. However, some of the above-described devices have charging function. When the charged-type battery is mounted on the device as the device is connected to the external power supply, the device causes the charged-type battery to be charged.
However, on that occasion, the non-charged battery is mounted thereon by mistake, trouble occurs such as liquid leakage, damage, or so forth with the result of charging. For that reason, in the conventional manner, the non-charged-type battery is discriminated from the charged-type battery. As the manner for discriminating the non-charged-type battery from the charged-type battery, a switch is used for switching the case of the non-charged-type battery to the case of the charged-type battery.
However, even though two cases are switched according to demand with each other, in this manner, sometimes switching of the switch is forgotten, or so forth, therefore it is imperfect, and cost is required.
In view of the foregoing, it is an object of the present invention, in order to overcome the above-mentioned problems, to provide a power supply unit capable of preventing failure charging on the occasion of use of the non-charged-type battery described-above.
According to a first aspect of the present invention, in order to achieve the above-mentioned object, there is provided a power supply unit which comprises an electric circuit device including a connecting means for connecting the electric circuit device to an external power supply, a positive electrode terminal connected to a positive side output terminal of the connecting means, a first negative electrode terminal connected to a switch terminal which becomes OFF as the external power supply is connected to the connecting means, and a second negative electrode terminal connected to a negative side output terminal of the connecting means, a non-charged-type battery case including a positive terminal provided corresponding to the positive electrode terminal, and a negative terminal provided corresponding to the first negative electrode terminal, and a charged-type battery case including a positive terminal provided corresponding to the positive electrode terminal, and a first and a second negative terminals provided corresponding to the first and the second negative electrode terminals respectively.
According to a second aspect of the present invention, in the first aspect, there is provided a power supply unit, wherein the connecting means is a power supply jack consisting of a jack-receiver for receiving a connecting connector of the external power supply, and a power supply jack having the positive side output terminal, a switch terminal, and a first, a second, and a third jack terminals which become the negative side output terminal.
According to a third aspect of the present invention, in the first or the second aspect, there is provided a power supply unit, wherein the electric circuit device is provided with an accommodation room for accommodating the non-charged-type battery case or the charged-type battery case, when the non-charged-type battery case is accommodated to be mounted, the positive electrode terminal and the first negative electrode terminal are connected to the positive terminal and the negative terminal of the non-charged-type battery case respectively, while when the charged-type battery case is accommodated to be mounted, the positive electrode terminal and the first and the second negative electrode terminals are connected to the positive terminal and the first and the second negative terminals of the charged-type battery case respectively.
According to a fourth aspect of the present invention, any of the first to the third aspects, there is provided a power supply unit, wherein the electric circuit device is supplied with power from the connecting means and/or the positive electrode terminal.
The above and further objects and novel features of the invention will be more fully understood from the following detailed description when the same is read in connection with the accompanying drawings. It should be expressly understood, however, that the drawings are for purpose of illustration only and are not intended as a definition of the limits of the invention.